1. Field of the Invention
This invention relates to a film rewinding device for movie cameras in which two different types of film magazines can be used selectively.
2. Description of the Prior Art
Generally, in film magazines available on the market for movie cameras, an anti-backup mechanism is provided on the film take-up core to prevent slack of the film in the magazine. A device for rewinding the film of such a magazine (hereinafter referred to as a type A magazine) has been already proposed in Japanese Patent Publication No. 15467/1970. U.S. Pat. No. 3,599,894 and Japanese Patent Publication No. 35238/1970 disclose cameras using a magazine provided with an anti-backup means and arranged such that when a part of the take-up shaft is pushed, said anti-backup means is moved to its inoperative position to allow both forward and reverse rotations (such magazine being hereinafter referred to as a type B magazine).
With the type A magazine, if film is to be removed, it is first advanced by a claw, while the take-up shaft is locked against rotation, and then the film may be rewound by operation of the claw. On the other hand, the type B magazine is so constructed as to allow both forward and reverse rotations of the take-up shaft, so that it is possible to rewind the film without making any forward feed independent of the take-up shaft before such rewind. In this case, the forward and rearward feed is effected by the operation of a claw and the take-up shaft.
Rewinding of the film is a cinematic photographing technique generally used for effecting overlaps, double exposure or reverse photographing. "Overlap" is accomplished by following the steps of a fadeout exposure (forward rotation), a rewind (reverse idle exposure) and a fadein exposure (forward rotation). "Double exposure" is effected by the successive steps of a normal photographing (forward rotation), a rewind and a normal photographing (forward rotation). "Reverse photographing" is effected by the successive steps of an idle feed (forward rotation), a reverse photographing (rewind rotation) and an idle feed rewind (forward rotation). Thus, the length of film rewound is usually determined by the magnitude of forward feed in the stage immediately before an actual rewind. Therefore, in order to accurately reproduce said photographing techniques in practical performances, it becomes necessary to operably associate the rewind counter with the operation in the stage just preceding the actual rewind. Hence, in the following description, when the phase "at the time of rewind" is used, it includes the forward feed in the stage just before the actual rewind. Also, for effecting proper fadein and fadeout when accomplishing a desired overlap, it is necessary to properly change the shutter opening angle and iris aperture.